The present invention relates to trailer hitches and, more particularly, to a novel triple fail-safe latch mechanism for a hitch assembly used to interconnect a towing vehicle to a drawn vehicle.
Conventionally a towing vehicle is interconnected to a drawn vehicle by mounting on the towing vehicle a hitch assembly. A coupling element, such as an eye, is provided on the drawbar of the drawn vehicle. The hitch assembly generally comprises a body or frame having a forward portion which terminates in a flange area designed for mounting on the towing vehicle, a base portion from which projects a pair of spaced webs, and a rear portion which flows smoothly from the base portion into a solid hook or pintle. Disposed adjacent the pintle is a cavity. Extending over the frame cavity and interposed the webs, is a pivotally mounted latch which has a notch intermediate its ends. A pawl is also interposed the webs and partially overlies the latch, with one end of the pawl in seated relation in the notch of the latch. Typically a spring is used to bias the the pawl downwardly into seated relation in the notch of the latch. The other end of the pawl is pivotally mounted on a pin having a handle used to laterally displace the pawl from its position in the notch.
The disadvantage with the conventional design is that, if the pawl spring is damaged or becomes defective, the pawl would rotate freely about its pivot axis, and the latch likewise would be "free-floating", i.e., enjoying unrestricted vertical movement. In such a condition, the coupling element on the drawn vehicle may easily disengage from the pintle. It can be appreciated that accidental disengagement of the coupling element from the pintle can result in serious property damage as well as personal injury.
Accordingly, it is a general object of the present invention to provide a novel latch mechanism for a trailer hitch which provides multiple safety features to prevent accidental disengagement of the latch.
Another object of the present invention is to provide a latch mechanism for a hitch assembly which will not accidentally disengage if the pawl becomes damaged or defective.
A further object of the invention is to provide a latch mechanism for a hitch assembly which provides a means to prevent lateral displacement of the latch when the rear end of the pawl is moved out of seated relationship with the notch.
Yet another object of the invention is to provide a means for preventing pivotal movement of the latch without lateral displacement of the latch, in a condition where the pawl is out of seated relationship with the notch.
A preferred embodiment of the proposed apparatus of the invention includes a hitch frame mounted on the towing vehicle with an upwardly extending pintle and a cavity disposed adjacent the pintle for receiving the coupling element mounted on the drawn vehicle. Extending over the frame cavity is a latch which has a forward end and a rear end with the rear end adjacent the pintle. The latch includes mounting means pivotally mounting the forward end of the latch accommodating upward movement of the rear end of the latch with pivotal movement of the latch. The mounting means also permits lateral displacement of the latch. A notch is disposed intermediate the ends of the latch. A spring-biased pawl generally overlies the latch and has a forward end pivotally mounted on the frame and a rear end adjacent and in seated relation in the notch of the latch. The pawl further includes a cam disposed adjacent its forward end. A recess or cam-engaging surface is disposed on the latch opposite the cam, to prevent lateral displacement of the latch with the rear end of the pawl moved out of seated relationship with the notch. The latch is fixedly secured to a pin, which provides the pivot axis for the latch. The pin includes a handle disposed exteriorly of the hitch assembly which is used to laterally displace the latch. The latch further includes a ledge disposed adjacent its forward end which seats within a shoulder of the frame opposing the ledge to prevent pivotal movement of the latch.
In operation, the pawl is manually lifted upwardly moving the rear end of the pawl out of seated engagement with the notch and the cam out of engagement with the cam surface. The handle on the latch pin is then shifted axially to move the latch's ledge away from the shoulder and free the latch for pivotal movement. The latch is then swung open, and held in an upright position. So positioned, the coupling element on the drawn vehicle may be inserted into the frame cavity and around the pintle. Once the coupling element is inserted, the handle of the latch pin may be released thereby allowing the latch to close over the cavity to effect a secure interconnection of the drawn vehicle to the towing vehicle.
With the construction described, it can be seen that the drawn vehicle is securely interconnected to the towing vehicle and that the latch is held in place by the cooperating action of three different safety features: the pawl spring urging the rear end of the pawl downwardly into seated relationship in the latch notch; the cam and its opposing cam-engaging surface preventing lateral displacement of the latch; and the latch ledge and its opposed frame shoulder preventing pivotal movement of the latch, without axial displacement.
These and other objects and advantages of the present invention will become more clearly understood from a consideration of the drawings and the following detailed description of a preferred embodiment.